add user ratings

Author: Anthony Li

backend/market/models.py

@@ -5,7 +5,7 @@
 from django.conf import settings
 from django.contrib.auth.models import AbstractUser
 from django.core.exceptions import ValidationError
-from django.core.validators import MinValueValidator
+from django.core.validators import MinValueValidator, MaxValueValidator
 from django.db import models
 from phonenumber_field.modelfields import PhoneNumberField
 
@@ -63,7 +63,6 @@ class Tag(models.Model):
     def __str__(self):
         return self.name
 
-
 class Listing(models.Model):
     class Meta:
         indexes = [
@@ -177,3 +176,30 @@ def approximate_location(self):
     def save(self, *args, **kwargs):
         self.full_clean()
         super().save(*args, **kwargs)
+
+class Rating(models.Model):
+    class RatingType(models.TextChoices):
+        BUYER = "BUYER", "Buyer Rating"
+        SELLER = "SELLER", "Seller Rating"
+    
+    class Meta:
+        constraints = [
+            models.UniqueConstraint(fields=["reviewer", "reviewed_user", "listing"], name="unique_rating_market")
+        ]
+        indexes = [
+            models.Index(fields=["reviewer"]),
+            models.Index(fields=["reviewed_user"]),
+            models.Index(fields=["listing"]),
+            models.Index(fields=["created_at"]),
+        ]
+
+    reviewer = models.ForeignKey(User, on_delete=models.CASCADE, related_name="ratings_given")
+    reviewed_user = models.ForeignKey(User, on_delete=models.CASCADE, related_name="ratings_received")
+    listing = models.ForeignKey(Listing, on_delete=models.CASCADE, related_name="ratings")
+    score = models.PositiveIntegerField(validators=[MinValueValidator(1), MaxValueValidator(5)])
+    rating_type = models.CharField(max_length=10, choices=RatingType.choices, default=RatingType.BUYER)
+    comment = models.TextField(blank=True)
+    created_at = models.DateTimeField(auto_now_add=True)
+    
+    def __str__(self):
+        return f"Rating of {self.score} for {self.reviewed_user} by {self.reviewer}"

backend/market/serializers.py

@@ -14,7 +14,7 @@
 )
 
 from market.mixins import ListingTypeMixin
-from market.models import Category, Item, Listing, ListingImage, Offer, Sublet, Tag
+from market.models import Category, Item, Listing, ListingImage, Offer, Rating, Sublet, Tag
 
 
 User = get_user_model()
@@ -443,3 +443,54 @@ class Meta:
 
     def get_favorite_count(self, obj):
         return obj.favorites.count()
+
+class RatingSerializer(ModelSerializer):
+    reviewer = UserSerializer(read_only=True)
+
+    class Meta:
+        model = Rating
+        fields = [
+            "id", 
+            "reviewer", 
+            "reviewed_user", 
+            "listing", 
+            "score", 
+            "rating_type", 
+            "comment", 
+            "created_at"
+            ]
+        read_only_fields = ["id", "created_at", "reviewer", "rating_type"]
+
+    def validate(self, attr):
+        reviewer = self.context["request"].user
+        reviewed_user = attr["reviewed_user"]
+        listing = attr["listing"]
+
+        if reviewer == reviewed_user:
+            raise ValidationError("You cannot review yourself.")
+        
+        is_seller = listing.seller == reviewer
+        is_buyer = listing.offers_received.filter(user=reviewer).exists()
+        if not is_seller and not is_buyer:
+            raise ValidationError("You can only rate users on listings you have interacted with.")
+        
+        target_is_seller = listing.seller == reviewed_user
+        target_is_buyer = listing.offers_received.filter(user=reviewed_user).exists()
+        if not target_is_seller and not target_is_buyer:
+            raise ValidationError("You cannot rate a user who is not on either side of the transaction.")
+        attr["rating_type"] = "SELLER" if is_seller else "BUYER"
+
+        return attr
+
+
+    def validate_comment(self, value):
+        if self.contains_profanity(value):
+            raise ValidationError("The comment contains inappropriate language.")
+        return value
+
+    def contains_profanity(self, text):
+        return predict([text])[0]
+
+    def create(self, validated_data):
+        validated_data["reviewer"] = self.context["request"].user
+        return super().create(validated_data)

backend/market/urls.py

@@ -9,8 +9,11 @@
     Offers,
     OffersMade,
     OffersReceived,
+    Ratings,
     Tags,
+    UserBuyerRatings,
     UserFavorites,
+    UserSellerRatings,
     get_current_user,
     get_phone_status,
     send_verification_code,
@@ -49,6 +52,23 @@
         "listings/<listing_id>/offers/",
         Offers.as_view({"get": "list", "post": "create", "delete": "destroy"}),
     ),
+    # Ratings for a listing (list + create)
+    path(
+        "listings/<listing_id>/ratings/",
+        Ratings.as_view({"get": "list", "post": "create"}),
+        name="listing-ratings",
+    ),
+    # Current user's received ratings by type
+    path(
+        "user/ratings/buyer/",
+        UserBuyerRatings.as_view(),
+        name="user-ratings-buyer",
+    ),
+    path(
+        "user/ratings/seller/",
+        UserSellerRatings.as_view(),
+        name="user-ratings-seller",
+    ),
     # Image Creation
     path("listings/<listing_id>/images/", CreateImages.as_view()),
     # Image Deletion

backend/market/views.py

@@ -16,7 +16,7 @@
 from rest_framework.response import Response
 
 from market.mixins import DefaultOrderMixin
-from market.models import Listing, ListingImage, Offer, Tag
+from market.models import Listing, ListingImage, Offer, Rating, Tag
 from market.pagination import PageSizeOffsetPagination
 from market.permissions import (
     IsSuperUser,
@@ -31,6 +31,7 @@
     ListingSerializerList,
     ListingSerializerPublic,
     OfferSerializer,
+    RatingSerializer,
     TagSerializer,
     UserSerializer,
 )
@@ -189,7 +190,7 @@ def retrieve(self, request, *args, **kwargs):
             serializer_class = ListingSerializer
         else:
             serializer_class = ListingSerializerPublic
-        serializer = serializer_class(instance)
+        serializer = serializer_class(instance, context={"request": request})
         return Response(serializer.data)
 
 
@@ -342,6 +343,38 @@ def list(self, request, *args, **kwargs):
         return super().list(request, *args, **kwargs)
 
 
+class Ratings(mixins.CreateModelMixin, mixins.ListModelMixin, viewsets.GenericViewSet):
+    serializer_class = RatingSerializer
+    permission_classes = [IsAuthenticated | IsSuperUser]
+
+    def get_queryset(self):
+        return Rating.objects.filter(listing_id=self.kwargs["listing_id"])
+    
+    def create(self, request, *args, **kwargs):
+        data = request.data.copy()
+        data["listing"] = int(self.kwargs["listing_id"])
+        serializer = self.get_serializer(data=data)
+        serializer.is_valid(raise_exception=True)
+        serializer.save()
+        return Response(serializer.data, status=status.HTTP_201_CREATED)
+
+class UserBuyerRatings(ListAPIView, DefaultOrderMixin):
+    serializer_class = RatingSerializer
+    permission_classes = [IsAuthenticated | IsSuperUser]
+    default_ordering = ["-created_at"]
+
+    def get_queryset(self):
+        return Rating.objects.filter(reviewed_user=self.request.user, rating_type="BUYER")
+
+class UserSellerRatings(ListAPIView, DefaultOrderMixin):
+    serializer_class = RatingSerializer
+    permission_classes = [IsAuthenticated | IsSuperUser]
+    default_ordering = ["-created_at"]
+
+    def get_queryset(self):
+        return Rating.objects.filter(reviewed_user=self.request.user, rating_type="SELLER")
+
+
 @api_view(["POST"])
 @permission_classes([IsAuthenticated])
 def send_verification_code(request):